import 'package:flutter/material.dart';

// 保持状态的容器
class KeepAliveWrapper extends StatefulWidget {
const KeepAliveWrapper(
{Key? key, @required this.child, this.keepAlive = true})
: super(key: key);
final Widget? child;
final bool keepAlive;
@override
State<KeepAliveWrapper> createState() => _KeepAliveWrapperState();
}
class _KeepAliveWrapperState extends State<KeepAliveWrapper>
with AutomaticKeepAliveClientMixin {
@override
Widget build(BuildContext context) {
return widget.child!;
}
@override
bool get wantKeepAlive => widget.keepAlive;
@override
void didUpdateWidget(covariant KeepAliveWrapper oldWidget) {
if (oldWidget.keepAlive != widget.keepAlive) {
// keepAlive 状态需要更新，实现在 AutomaticKeepAliveClientMixin 中
updateKeepAlive();
}
}}